The present invention generally relates to test equipment and more particularly to a system for exercising the transducer and acoustic panel of a homing torpedo by means of an external attachment.
Two previous known attempts have been made for generating artificial target signals in order to test homing devices. Both attempts used a device that is called either an acoustic calibration transducer or an inverse transducer. One system included the use of four spaced transducer elements mounted on a platform adapted for rotation. The platform was eccentrically offset and tilted with respect to the transducer axis. The entire assembly was immersed in a bath of oil with one side clamped to the face of the transducer. The platform was then rotated for generating varying target angles within the homing system transducer. The problem with the system included unexpected nulls and peaks due to a varying geometry in the near field causing the eventual abandonment of the effort. A second system was devised that eliminated some of the previous problems by using stationary geometry. A number of calibration elements were located at predetermined distances and directions from the transducer face. Coupling between the homing system transducer and the calibration elements was provided by a water column. Transmitting through elements in different quadrants permitted generation of up-down, left-right commands, but only at fixed angles. The detrimental effects of contamination of the transducer surfaces was minimized by circulating the water. This resulted in a large unwieldy calibration system. In addition, the testing of the output level was not possible due to the limited size of the water tank and the interference caused by reverberation within the tank.